An early analysis of water samples suggests illegal dumping as a possible cause for the transformation. "We suspect that somebody dumped artificial coloring in the water because he thought the typhoon yesterday would cause heavy rain, and nobody would notice [the color]," bureau chief Jianfeng Xiao, told China News. "It turned out there wasn't heavy rainfall yesterday, so the evidence is left behind."

According to Jennifer Hui at Shanghaist, the dominant theory remains that it was dye. Especially because this scenario resembles a similar incident two years ago on the Yangzee River, which was briefly turned to the color of blood by people from dye workshops dumping waste into the water illegally.